Gulf of Maine Seasonal Sea Surface Temperature Update
Seasonal Patterns in Sea Surface Temperatures
About the Updates:
Over the past decade, scientists at the Gulf of Maine Research Institute have led a body of research that highlights the rapid pace of warming in the Gulf of Maine. To keep you informed, we share seasonal updates about conditions in the Gulf of Maine.
Note About the Data: The figures in this report are creating using remotely-sensed satellite data as part of publicly funded research efforts. Satellite SST data was obtained from NOAA’s National Center for Environmental Information (NCEI), with all maps and figures displaying NOAA’s Optimum Interpolation Sea Surface Temperature Data.
Note on Preliminary Data: This dataset has a 2-week latency period, during which values may change due to quality control measures. Any data within 14 days of the publishing date may be subject to change.
The Gulf of Maine Region
For analyses like these, it is important to be clear about the spatial extent that “defines” the Gulf of Maine (Figure 1), as different borders could produce different numbers. The spatial extent we use as the “Gulf of Maine” is displayed below. This area is consistent with previous reports and publications GMRI has produced.
For this seasonal report, we present an analysis of SST for Summer (June 1st - August 31st).
Highlights
The average SST for the Gulf of Maine during the summer of 2022 was 62.14°F. Making it the 3rd hottest summer on record for the period of 1982-2022. These temperatures are 3.89°F above the long-term (1982-222) Summer average of 58.25°F.
Weekly Temperatures
In the below table, we highlight how the SST for each week this summer compares to a 30-year baseline period (climatological averages from 1982 through 2011).
The observed SST, long-term average SST, as well as departures from the long-term average (SST anomalies) are shown.
| Weekly Sea Surface Temperatures - Summer | ||||||
|---|---|---|---|---|---|---|
| Summer (June 1st - August 31st) | ||||||
| One-Week Period | Observed Temperature | Climatological Average | Temperature Anomaly | |||
| °F | °C | °F | °C | °F | °C | |
| Jun 01 - Jun 04 | 53.5 | 12.0 | 49.6 | 9.78 | 3.92 | 2.18 |
| Jun 05 - Jun 11 | 55.5 | 13.1 | 50.9 | 10.50 | 4.61 | 2.56 |
| Jun 12 - Jun 18 | 57.4 | 14.1 | 52.7 | 11.50 | 4.78 | 2.66 |
| Jun 19 - Jun 25 | 56.6 | 13.7 | 54.4 | 12.50 | 2.21 | 1.23 |
| Jun 26 - Jul 02 | 59.3 | 15.1 | 56.2 | 13.40 | 3.09 | 1.72 |
| Jul 03 - Jul 09 | 61.2 | 16.2 | 57.8 | 14.30 | 3.43 | 1.90 |
| Jul 10 - Jul 16 | 62.6 | 17.0 | 59.2 | 15.10 | 3.38 | 1.88 |
| Jul 17 - Jul 23 | 63.6 | 17.6 | 60.3 | 15.70 | 3.26 | 1.81 |
| Jul 24 - Jul 30 | 64.8 | 18.2 | 61.3 | 16.30 | 3.47 | 1.93 |
| Jul 31 - Aug 06 | 66.5 | 19.2 | 62.0 | 16.70 | 4.53 | 2.52 |
| Aug 07 - Aug 13 | 67.7 | 19.8 | 62.4 | 16.90 | 5.27 | 2.93 |
| Aug 14 - Aug 20 | 65.7 | 18.7 | 62.5 | 16.90 | 3.23 | 1.79 |
| Aug 21 - Aug 27 | 66.9 | 19.4 | 62.2 | 16.80 | 4.66 | 2.59 |
| Aug 28 - Aug 31 | 67.1 | 19.5 | 61.9 | 16.60 | 5.20 | 2.89 |
| Data Source: NOAA OISSTv2 Daily Sea Surface Temperature Data. | ||||||
| Climatology Reference Period: 1982-2011. | ||||||
Monthly Statistics
Looking at monthly averages (as opposed to week-by-week conditions), we see that August showed the largest deviation from the long-term climatological average, with an average SST anomaly of 4.56°F. All days this season met the criteria to be considered a marine heatwave, and each month was 3.36°F or more above the 1982-2011 climatological average.
| Month | Observed Temperature | Climatological Average | Temperature Anomaly | Temperature Progression | |||
|---|---|---|---|---|---|---|---|
| °F | °C | °F | °C | °F | °C | High/Low °F | |
| Jun | 56.5 | 13.6 | 52.8 | 11.6 | 3.75 | 2.08 | |
| Jul | 62.9 | 17.2 | 59.5 | 15.3 | 3.36 | 1.87 | |
| Aug | 66.8 | 19.3 | 62.2 | 16.8 | 4.56 | 2.53 | |
| Data Source: NOAA OISSTv2 Daily Sea Surface Temperature Data. | |||||||
| Climatology Reference Period: 1982-2011. | |||||||
Seasonal Trends and Anomalies in Context
The Gulf of Maine is an area of particular interest to the scientific community because of the remarkable rate of warming it has experienced in recent years.
When looking at average summer temperatures, there is a clear long-term increase, with SST’s warming at a rate of 1.06°F per decade. A major factor driving this trend is a shift in the thermal regime that we began to observe around 2010.
This period of faster warming is part of what appears to be a distinct regime in the Gulf of Maine. The drivers of this (e.g., a weakening of the Atlantic Meridional Overturning Circulation and shifts in the path of the Gulf Stream) have been well-documented in the peer-reviewed literature, including through research by GMRI scientists.
How Does 2022 Compare?
2022 is among the warmest summers seen in the Gulf of Maine during this 40+ year period. When compared against all previous summers for which we have reliable satellite data (i.e., back to 1982), this year ranks 3rd among the hottest on record since 1982.
Marine Heatwave Timeline
The most commonly used definition of a “marine heatwave” (MHW) is when daily average SST’s exceed the 90th percentile of a climatological (i.e., 30-year) average for at least 5 consecutive days. Successive heatwave gaps of 2 days or less are considered part of the same event.
Using this broadly accepted definition, the Gulf of Maine has experienced MHW conditions through summer 2022 A brief reprieve in mid-May lasted less than two days, so it did not constitute a break in the heatwave event.
Heatwave Anomaly Timeline
Presenting SST conditions in terms of anomalies (figure below) as opposed to absolute values (figure above) illustrates in greater detail the magnitude of MHW conditions throughout the summer.
The most extreme anomalies this summer occurred in August, with temperatures exceeding \(6°\)F above the climatological average.
Heatmap of Temperature Anomalies and Heatwave Events
Looking at the full record of daily SST anomalies in the Gulf of Maine (figure below), the distinct thermal regime shift beginning around 2010 is evident. Indeed, since 2012, the Gulf of Maine has experienced far more persistent MHW conditions (indicated by solid black lines) than at any other point in the satellite record.
Monthly Rankings Heatmap
Longest Heatwave on Record
This summer marked the conclusion of the Gulf of Maine’s longest heatwave event.
This event lasted a total of 535, and during that period temperatures were on average 3.87°F above temperatures observed during the climate reference period.
Spatial Distribution of Seasonal Anomalies
From a spatial perspective, the Gulf of Maine and surrounding areas experienced above average SST’s for much of the region during summer 2022, but with particularly warm patches to the south and east of Georges Bank. The highest seasonally averaged anomaly of any location above was 6.73°F.
Monthly Temperature Anomalies
Average monthly temperature anomalies are displayed below. The warmest anomalies were initially concentrated just south of the domain studied in this analysis in June, but by July temperatures within the Gulf of Maine were exceptionally hot, and by August waters in the Gulf of Maine and the surrounding areas were all experiencing monthly-averaged SST’s that were > 8°F warmer than during our climate reference period (1982-2011).
A work by Adam A. Kemberling
Akemberling@gmri.org